In-home receiver system

ABSTRACT

The in-home system comprises a complex main receiver (MR) and at least one standard receiver (AR). The main receiver (MR) receives the broadcast signals (HFIS) from the provider(s) and demodulates and/or decodes and/or descrambles (DEM) the broadcast signals (HFIS). A modulator (MOD) re-modulates the demodulated and/or decoded broadcast signals (MIS) onto a high-frequency carrier and provides this modulated signal (HFOS) to the standard receiver (AR). The demodulating, decoding, and/or descrambling (DEM) needs to be performed by the main receiver (MR) only, and is distributed via a high-frequency link to the standard receiver (AR) in the home environment. The main receiver (MR) comprises at least one tuner (TUi) with a tuner input (TUIi) for receiving the high-frequency input signal (HFIS) and a tuner output (TUOi) for supplying a tuner output signal (TOSi). A test signal generator (TSG) of the main receiver (MR) supplies a test signal (TSi) to the modulator (MODi) to obtain the high-frequency output signal (HFOSi). A directing circuit (DIR) directs the high-frequency output signal (HFOSi) to the tuner input (TUIi), and a test evaluator (TE) evaluates whether the tuner output signal (TUOi) is in conformance with the test signal (TSi). In this way, the performance of the system is checked.

FIELD OF THE INVENTION

The invention relates to an in-home receiver system, a main receiver foruse in such an in-home receiver system, and a method of testing such anin-home receiver system.

BACKGROUND OF THE INVENTION

In present audio and/or video receiver set-up's, it becomes more andmore important to be able to receive many different broadcast systems.Besides the terrestrial or satellite analog television signalstransmitted by air or supplied on the cable, digital broadcastingbecomes more popular. Also, data exchange between the provider and theuser of the receiver is becoming more important.

Usually, present systems are upgraded to receive these new broadcasts byadding a separate set-top box to the television receiver. Also,television receivers are appearing on the market which incorporate thefunctionality of the set-top box. In the following, receiver refers to aset-top box receiver, a television receiver, an audio receiver or anyother receiver for receiving audio and/or video broadcast signals.

The receiver may comprise a plurality of tuners, for example, a tunerfor receiving the standard analog broadcast signals, a tuner forreceiving digital broadcast signals, and a tuner for out-of-band or forexample DOCSIS signaling. The out-of-band signaling may be based on thesame protocols as used in internet cable modems, and may provide anup-stream channel to the provider, or internet access.

The receiver further comprises a demodulator and/or decoder whichgenerates the base band signal. The base band signal, for example, maybe an analog CVBS signal, an audio signal, or an MPEG data stream, or adecoded MPEG data stream.

For the further in-home re-distribution of the signals, a modulator ofthe receiver modulates the base band signal on a high-frequency carriersuch that the modulated signal can be received by a standard analogtuner, which, for example, is available in another television receiveror a video recorder in the home.

The performance of the receiver may be negatively influenced by itsincreasing complexity.

SUMMARY OF THE INVENTION

It is an object of the invention to provide provisions in the receiverfor testing the performance of the receiver.

A first aspect of the invention provides an in-home receiver system witha main receiver and at least one further receiver, the main receivercomprising: at least one tuner with a tuner input for receiving ahigh-frequency input signal and a tuner output for supplying a tuneroutput signal, at least one modulator for receiving a modulator inputsignal to supply a high-frequency output signal to the at least onefurther receiver, a test signal generator for supplying a test signal tothe at least one modulator, a directing circuit for directing thehigh-frequency output signal to the tuner input, and a test evaluatorfor evaluating whether the tuner output signal is in conformance withthe test signal.

A second aspect of the invention provides a main receiver for use in anin-home system as claimed in claim 14. A third aspect of the inventionprovides a method of testing a main receiver of an in-home system asclaimed in claim 15. Advantageous embodiments are defined in thedependent claims.

The in-home system comprises a main receiver and at least one furtherreceiver further referred to as auxiliary receiver.

The main receiver receives the broadcast signals from the provider(s)and demodulates and/or decodes and/or descrambles the broadcast signals.A modulator re-modulates the demodulated and/or decoded and/ordescrambles broadcast signals onto a high-frequency carrier and providesthis modulated signal, or this modulated signal combined with the analogbroadcast signal to the standard auxiliary receiver. The demodulating,decoding, and/or descrambling needs to be performed by the main receiveronly, and is distributed via a high-frequency link to other receivers inthe home environment. These other receivers do not need thedemodulating, decoding, and/or descrambling functionality.

The main receiver comprises at least one tuner with a tuner input forreceiving a high-frequency input signal and a tuner output for supplyinga tuner output signal. Usually, the high-frequency input signal is thebroadcast signal received from the provider, but it might be an in-homegenerated signal, for example by a portable audio-visual apparatustransmitting the audio and/or video information at a frequency in ahigh-frequency band (in the literature also referred to as RF-band,which is, for example, a radio broadcast band (for example, theFM-band), or a television band (for example, the UHF-band).

A test signal generator of the main receiver supplies a test signal tothe modulator to obtain a high-frequency output signal. A directingcircuit directs the high-frequency output signal to the tuner input, anda test evaluator evaluates whether the tuner output signal is inconformance with the test signal. The result of this conformance testmay then be communicated to the set controller/micro-processor/etc. viae.g. a digital bus or a signaling line indicating PASS or FAIL.

In this manner, it is possible to test the performance of the mainreceiver. For example, it is possible to check whether the tuner and themodulator are still functioning, or whether the modulator still providesthe intended carrier frequency.

The main receiver may comprise several tuners and modulators. In acomplex system, the test provision becomes even more interesting, aswill become clear from the embodiments of the invention as claimed fromclaim 6 onwards.

In an embodiment of the invention as claimed in claim 2, the directingcircuit comprises a switch for supplying either the high-frequency inputsignal or the high-frequency carrier (also referred to as thehigh-frequency output signal from the modulator) to the tuner inputunder control of a switching signal generated by a switch controlcircuit of the main receiver.

In an embodiment of the invention as claimed in claim 3, the directingcircuit comprises a series arrangement of a high-frequency coupler and aswitch being controlled by a switching signal generated by a switchcontrol circuit. The series arrangement is arranged between the tunerinput and an output of the modulator to supply either the high-frequencyinput signal when the switch is open or the high-frequency input signaltogether with the high-frequency output signal to the tuner input whenthe switch is closed.

The commonly known passive high-frequency coupler couples thehigh-frequency signal at its input to another high-frequency signal.

In an embodiment of the invention as claimed in claim 4, the test signalis an analog signal which comprises a sine wave at a predeterminedfrequency, or the test signal is digital signal which comprises a bitsequence. In general, the test signal will be selected to be suitable totest the modulator and tuner under test.

In an embodiment of the invention as claimed in claim 5, the test signalgenerator comprises a modulator frequency controller which controls theat least one modulator to vary a frequency of the high-frequency outputsignal through a desired frequency band. This enables to check whetherthe tuner or tuners are still able to receive the broadcasts within thedesired frequency band.

In an embodiment of the invention as claimed in claim 6, the in-homesystem comprises a plurality of tuners, each with a tuner input forreceiving a high-frequency input signal and a tuner output for supplyinga tuner output signal. A selector selects one of the plurality oftuners. A test evaluator produces a conformance signal if the outputsignal of the selected one of the tuners is in conformance with the testsignal. The selector further selects another one of the plurality oftuners if the conformance signal indicates that the output signal of theselected one of the tuners is in not in conformance with the testsignal.

All the tuners can be tested by checking whether the output signal is inconformance with the test signal modulated by the modulator on thehigh-frequency carrier. If it is detected that one of the tuners doesnot function properly, this can be brought to the attention of the useror a repair technician.

In an embodiment of the invention as claimed in claim 7, the controllercomprises a tuner controller which controls one tuner (or more tuners,if required) to scan through at least part of the high-frequency band tobe received. The scan may be performed through the complete band orthrough part of the band. A detector detects at which frequencies in thehigh-frequency band a broadcast signal is present and a frequencysetting circuit sets a modulation frequency of the modulator or themodulators to interleave with the frequencies in the least part of thehigh-frequency band at which a broadcast signal is present.

The scan provides information on which channels a broadcast signal ispresent. The modulator(s) will be controlled to modulate thehigh-frequency signal in channels which are not occupied by broadcastsignals. This automatic system has the advantage that the user does notneed to adjust the modulators manually to an optimal frequency. Often,this difficult process leads to a non-optimal operation of the systembecause the modulators are not adjusted carefully enough andinterferences occur.

The automatic system in accordance with this embodiment of the inventionmay perform additional tests on the suitability of the channel selectedfor the modulator. For example, the modulator may supply a non-modulatedcarrier only, the signal at the tuner output is an indication whetherany interference occurs.

In an embodiment of the invention as claimed in claim 8, a timingcircuit causes the test signal to be supplied at regular time intervals.In this manner, it is possible to take changes into account. Byregularly checking the presence of broadcast signals in the band, amodulator frequency can be adjusted if a channel appears to be used by anew broadcast or by a broadcast which occupies a channel during apredetermined period of the day only. Further it is possible tocompensate for drift of the modulator frequency, for example due toaging.

In an embodiment of the invention as claimed in claim 9, the mainreceiver comprises a plurality of tuners with respective tuner inputswhich receive the high-frequency input signal and which have respectivetuner outputs for supplying tuner output signals.

An input terminal is available to connect an input coaxial cable whichsupplies the high-frequency input signal with a broadcast signal. Afirst high-frequency splitter splits the signal on the input coaxialcable into a plurality of signals which are supplied as thehigh-frequency input signals to the tuner inputs.

A high-frequency demodulator circuit receives the tuner output signalsto supply respective demodulated or decoded video signals, which forexample are a CVBS signal or a QPSK or QAM modulated MPEG data stream,to modulate them on a high-frequency carrier wave.

A plurality of modulators receive the respective modulator input signalsand supply the high-frequency output signals to a high-frequencycombiner which combines the high-frequency output signals into aplurality of combined high-frequency output signals. A first combinedhigh-frequency output signal is supplied to a first auxiliary receivervia a first output coaxial cable. A second combined high-frequencyoutput signal is supplied to a second auxiliary receiver via a secondoutput coaxial cable. If more auxiliary receivers are present, thecombiner has to supply more combined high-frequency output signals.

Preferably, the modulator input signals are the demodulated or decodedvideo signals. This allows the auxiliary receivers to be simple as theydo not require the extra demodulators and decoders (and descramblers ifapplicable). It is possible to supply the tuner output signals (whichmay be analog or digital (for example, an MPEG stream)) to thedemodulators. This is especially relevant for the signals which do notrequire special demodulators or decoders in the auxiliary receivers.

A test signal generator supplies the test signal to at least one of themodulators, the directing circuit directs a combined high-frequencyoutput signal to an input of a combiner which combines this combinedhigh-frequency output signal with the high-frequency input signal. Atest evaluator evaluates whether the tuner output signal is, or thesignals are, in conformance with the test signal. The test evaluator maycommunicate the outcome of the test to a microcontroller of thereceiver. The microcontroller takes the required action, for example,warns the user that the receiver does not operate properly.

In an embodiment of the invention as claimed in claim 10, the combineris a high-frequency coupler coupled to the input coaxial cable. A secondhigh-frequency splitter is coupled to the first mentioned high-frequencycoupler for supplying the high-frequency input signal to a secondhigh-frequency coupler and a third high-frequency coupler, the secondhigh-frequency coupler is coupled to the first output coaxial cable anda third high-frequency coupler is coupled to the second output coaxialcable. In this manner, the signal on the input coaxial cable is loopedthrough to the output coaxial cables and is directly available to theauxiliary receivers.

In an embodiment of the invention as claimed in claim 11, the mainreceiver comprises a high-frequency switching matrix which is able toconnect any high-frequency input to any high-frequency output. It isalso possible to connect the same input or output to several outputs orinputs, respectively (a so-called broadcast mode).

The switching matrix has inputs for receiving the high-frequency inputsignal from the high-frequency splitter, the high-frequency outputsignals of the modulators. The switching matrix has outputs to supplythe high-frequency input signals to the tuner inputs, and thehigh-frequency output signals to the high-frequency combiner.

The tuner output signals are supplied to the demodulator and the testsignal generator and need not be directed via the high-frequencyswitching matrix. The test signals are supplied to the modulator inputsas the modulator signals and also need not be directed via thehigh-frequency switching matrix.

This switching matrix has the advantage that it can be incorporated muchmore easily and effectively, and thus cheaper in an integrated circuit,this contrary to the high-frequency combiners. A further advantage isthat the loop-through from the signal on the input coaxial to the outputcoaxial cables can be performed by the switching matrix. Now, it canalso be checked whether this loop-through function is performingcorrectly.

In an embodiment of the invention as claimed in claim 12, thehigh-frequency switching matrix further has an input to receive thehigh-frequency output signal. This enables to check a double paththrough the switching matrix.

In an embodiment of the invention as claimed in claim 13, the mainreceiver further comprises a circuit for adding an upstream signalingstream onto the high-frequency input signal. This enables communicationto the provider, which is important when applications likevideo-on-demand or internet are required.

Especially if the cable set-top box receiver will merge into a digitalhome server box, multiple channels have to be received andre-distributed throughout the house, further increasing the number oftuners. Since most in-house networks will for a long time continue to bebased on coaxial cables, on the transmitter side increasing numbers ofhigh-frequency modulators will be needed.

The in-home system comprises a main receiver and at least one furtherreceiver. The main receiver receives the broadcast signals from theprovider(s) and demodulates and/or decodes the broadcast signals. Amodulator re-modulates the demodulated and/or decoded broadcast signalsonto a high-frequency carrier and provides this modulated signal or thisdecoded signal combined with the analog broadcast signal to the standardfurther receiver. The standard further receiver need not be able toprocess the signals (for example, digital television, MPEG streams,internet data) which the main receiver is able to process into base bandsignals.

These and other aspects of the invention are apparent from and will beelucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a block diagram of an embodiment of a system in accordancewith the invention,

FIG. 2 shows an embodiment of a directing circuit of the system,

FIG. 3 shows another embodiment a directing circuit of the system,

FIG. 4 shows an embodiment of a controlling circuit of the system,

FIG. 5 shows another embodiment of a controlling circuit of the system,

FIG. 6 shows a block diagram of an embodiment of a main receiver of thesystem in accordance with the invention, and

FIG. 7 shows a block diagram of another embodiment of a main receiver ofthe system in accordance with the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 shows a block diagram of an embodiment of a system in accordancewith the invention. The system comprises a main receiver MR and anauxiliary receiver AR.

The main receiver MR comprises a tuner TU, a controller CO, a modulatorMOD, a demodulator DEM, and a directing circuit DIR.

The tuner TU has an input TUI at which a high-frequency input signalHFIS of a broadcast is received and a tuner output TUO at which a lowfrequent tuner output signal TOS is supplied. Usually, thehigh-frequency input signal HFIS is supplied by an input coaxial cableCOI (shown in FIG. 6). Usually, the tuner output signal TOS is a baseband audio and/or video signal which may be encoded or which may be acomposite signal such as a CVBS signal.

The demodulator DEM receives the tuner output signal TOS and supplies ademodulated and/or decoded signal DMS suitable to be displayed on adisplay screen of the main receiver MR.

The modulator MOD has an input to receive a modulator input signal MISand an output to supply a high-frequency output signal HFOS to theauxiliary receiver AR. Usually, the modulator input signal MIS is thedemodulated and/or decoded signal DMS. The high-frequency output signalHFOS is supplied to the auxiliary receiver AR via a coaxial cable in afrequency range and with a modulation type suitable for a standardavailable broadcast receiver. The auxiliary receiver AR usually is ableto receive analog broadcast channels as transmitted in the VHF and theUHF bands. This set-up allows using standard available auxiliaryreceivers AR which need not be adapted to be able to receive anddemodulate or decode the broadcast signal which is processed by thetuner TU and the demodulator DEM of the main receiver MR. The tuner TUand the demodulator DEM, for example, may process a digital video signalwhich is MPEG coded. Usually, the main receiver MR comprises a furthertuner to receive the standard analog broadcast channels.

The controller CO generates a test signal TS which is supplied to theinput of the modulator MOD and a switching signal SCS which is suppliedto the directing circuit DIR. The controller CO receives the demodulatedsignal DMS, or the tuner output signal TOS. The switching signal SCS issupplied by a switch control circuit SCC of the controller CO.

The directing circuit DIR has an input to receive the high-frequencyoutput signal HFOS and an output to supply the high-frequency outputsignal HFOS to the input TUI of the tuner TU.

The main receiver MR has a first mode wherein the high-frequency inputsignal HFIS is processed to be displayed, and a test mode wherein thecontroller CO provides the test signal TS to the modulator MOD. Themodulator MOD modulates the test signal on a high-frequency carrier toobtain the high-frequency output signal HFOS. The directing circuit DIRcouples the high-frequency output signal HFOS to the input TUI of thetuner TU under control of the switching signal SCS. The controller COreceives the demodulated signal DMS which is the demodulated testsignal, and compares the demodulated test signal with the generated testsignal TS to determine whether the main receiver MR is performingcorrectly. The controller CO may take an appropriate action or mayoutput a signal to a micro-controller if an incorrect performance isdetected.

FIG. 2 shows an embodiment of a directing circuit of the system.

The directing circuit DIR comprises a switch SW1 controlled by theswitching signal SCS which is generated by the switch control circuitSCC of the controller CO. A first input terminal of the switch SW1receives the high-frequency input signal HFIS, a second input terminalof the switch SW1 receives the high-frequency output signal HFOS fromthe modulator MOD, and the common terminal of the switch SW1 isconnected to the tuner input TUI. In the normal receiving mode thecontrol signal SCS causes the switch to supply the high-frequency inputsignal HFIS to the tuner input TUI. In the test mode, the control signalSCS causes the switch to supply the high-frequency output signal HFOS tothe tuner input TUI.

FIG. 3 shows another embodiment a directing circuit of the system.

The directing circuit DIR comprises a high-frequency coupler HFC1 and aswitch SW2. The high-frequency coupler HFC1 and the switch SW2 arearranged in series between the output of the modulator MOD and the inputTUI of the tuner TU.

The high-frequency coupler HFC1 couples the input signal HFCS1 to thehigh-frequency input signal HFIS, usually with an insertion loss. Such acoupler is well known in the art.

The switching signal SCS which is generated by the switch controlcircuit SCC of the controller CO controls the switch SW2 to be open inthe normal receiving mode and to be closed in the test mode.

FIG. 4 shows an embodiment of a controlling circuit of the system. Thecontroller CO comprises a test signal generator TSG, a timing circuitTIM, a modulator frequency controller MFC, a detector DET, and theswitch control circuit SCC.

The test signal generator TSG generates the test signal TS. The testsignal TS may be analog or digital. A suitable analog test signal TS maybe a sine wave with a fixed frequency or with a varying frequency andwith a fixed or varying amplitude. The digital test signal TS may be abit sequence which may be digitally modulated. The test signal TS willbe modulated on a high-frequency carrier by the modulator MOD.

The modulator frequency controller MFC supplies a modulator frequencycontrol signal MFI to the modulator MOD to control the channel frequencyof the high-frequency output signal HFOS. The modulator frequencycontroller MFC may vary a frequency of the high-frequency output signalHFOS through a desired frequency band.

The controlling circuit CO further comprises a detector DET whichreceives the tuner output signal TOS, compares the received tuner signalTOS with the test signal TS and outputs an indication signal IS toindicate the outcome of the test. This enables to check whether thetuner TU (or tuners TUi if the main receiver comprises more than onetuner) is still able to receive the broadcasts within the desiredfrequency band.

The timer TIM may control the test signal generator TSG to provide thetest signal TS at regular intervals or at certain occasions such as thefirst time the receiver is switched on every day. For example, it may beregularly tested whether the modulator MOD still produces the correctchannel frequency, and to correct a shift if it is detected. This allowsto compensate for drift of the modulator frequency, for example due toaging. The timer TIM further controls the switch control circuit SCC tocouple the high-frequency output signal HFOS to the tuner input TUIduring the test mode, and the frequency controller MFC to provide adesired frequency or frequency sweep.

It is possible to use the test signal generator TSG during production ofthe main receiver only, especially if it has only to be tested if allthe tuners TUi and all the modulators MODi function correctly.

FIG. 5 shows another embodiment of a controlling circuit of the system.The controller CO comprises a tuner controller TUC, a detector DET, afrequency setting circuit FSC, and a controller CO1.

The controller CO1 controls the tuner controller TUC to supply a tunerfrequency control signal TFI to control the tuner TU (or more tunersTUi, if required) to scan through at least part of the high-frequencyband to be received by the main receiver MR. The scan may be performedthrough the complete band or through part of the band.

The detector DET receives the tuner output signal TOS to detect at whichfrequencies in the high-frequency band a broadcast signal is present,and provides this information DBC to the controller CO1.

The controller CO1 controls a frequency setting circuit FSC to supply amodulator frequency setting signal to the modulator MOD to set amodulation frequency of the modulator MOD (or the modulators MODi) tointerleave with the frequencies in the least part of the high-frequencyband at which a broadcast signal is present.

The scan provides information on which channels a broadcast signal ispresent. The modulator MOD will be controlled to modulate thehigh-frequency output signal HFOS in channels which are not occupied bybroadcast signals. This automatic system has the advantage that the userdoes not need to adjust the modulators manually to an optimal frequency.Often, this difficult process leads to a non-optimal operation of thesystem because the modulators are not adjusted carefully enough andinterferences occur.

The timer TIM as shown in FIG. 4 may also be used in the controller COshown in FIG. 5. By regularly checking the presence of broadcast signalsin the band, a modulator frequency can be adjusted if a channel appearsto be used by a new broadcast or by a broadcast which occupies a channelduring a predetermined period of the day only.

The embodiments of FIG. 4 and FIG. 5 may be combined.

FIG. 6 shows a block diagram of an embodiment of a main receiver of thesystem in accordance with the invention.

The main receiver MR receives the high-frequency input signal HFIS froma provider PRO via an input coaxial cable at an input terminal INT. Themain receiver MR supplies a high-frequency output signal HFOS1 at theoutput terminal OT1 via an output coaxial cable COO1 to an auxiliaryreceiver AR1 and a high-frequency output signal HFOS2 at an outputterminal OT2 via an output coaxial cable COO2 to an auxiliary receiverAR2.

The main receiver MR comprises a plurality of tuners TU1 to TUn and aplurality of modulators MOD1 to MODm. A particular tuner is denoted byTUi, and a particular modulator is denoted by MODi. Each of the tunersTUi has a tuner input TUIi to receive a high-frequency input signalHFISi and a tuner output TUOi to supply a low frequent tuner outputsignal TOSi.

A high-frequency splitter HFS1 has an input connected to a node N1 andsupplies the tuner input signals TUIi to the tuners TUi.

The demodulator DEM demodulates or decodes the tuner output signals TOSiinto demodulator output signals DESi (usually base band signals). InFIG. 6 some of the demodulator output signals DESi are digital signals.

A video switching matrix VSM receives the demodulator output signalsDESi and supplies the modulator input signals MOIi to the modulatorsMODi. The video switching matrix VSM selects the signal to be displayedon the main receiver, and selects which output signal DESi is directedto which modulator MODi. The output signals DESi are converted bydigital to analog converters DACi into the analog modulator inputsignals MOIi.

A high-frequency combiner HFC1 combines the high-frequency outputsignals HFOSi of the modulators MODi into three combined high-frequencysignals CHFOSi. The combined high-frequency signal CHFOS1 is supplied tothe output terminal OT1 via a high-frequency coupler HFC2, the combinedhigh-frequency signal CHFOS2 is supplied to the output terminal OT2 viaa high-frequency coupler HFC3, and the combined high-frequency signalCHFOS3 is supplied to the switch SW2.

A high-frequency coupler HFC1, a high-frequency coupler HFC4, and ahigh-frequency coupler HFC5 are arranged between the input terminal INTand the node N1 in this order.

The high-frequency coupler HFC1 supplies the input signal at the inputterminal INT to a splitter HFS2. The splitter HFS2 supplies the inputsignal at the input terminal INT to the output terminal OT1 via ahigh-frequency coupler HFC2 which acts as a combiner. The splitter HFS2supplies the input signal at the input terminal INT to the outputterminal OT2 via a high-frequency coupler HFC3 which acts as a combiner.Consequently, the high-frequency input signal HFIS is linked through tothe auxiliary receivers AR1 and AR2. These signals need not be modulatedon a carrier by the modulators MODi.

The high-frequency coupler HFC4 acts as a combiner to add the upstreamsignal US to the high-frequency input signal HFIS. The upstream signalUS may be a DOCSIS signal generated by a DOCSIS upstream signalingcircuit DOC.

The high-frequency coupler HFC5 acts as a combiner which adds thehigh-frequency output signal HFOS to the input signal during the testmode.

The directing circuit DIR comprises the switch SW2 and the combinerHFC5. It is also possible to use the directing circuit DIR shown in FIG.2.

The main receiver MR further comprises a controller CO which receivesthe tuner output signals TUOi (or the demodulator output signals DESi,not shown in FIG. 6) and supplies the test signals TSi to the modulatorsMODi. The controller CO supplies the switching signal SCS to the switchSW2 such that the combined high-frequency output signal CHFOS3 issupplied to the coupler HFC5 in the test mode only.

The controller comprises a test signal generator TSG which generates thetest signals TSi, a selector SEL which selects one of the tuner outputsignals TOSi, and a test evaluator TE which tests whether the selectedtuner output signal TOSi is in conformance with the test signal TSi. Thetest evaluator TE supplies a conformance signal CON to the selector SELto indicate whether the selected tuner output signal TOSi is inconformance with the test signal TSi. If conformance is detected, thecircuit loop from test signal TSi via modulator MODi, splitter HFC1,switch SW2, coupler HFC5, splitter HFS1 and tuner TUi is operatingcorrectly. If no conformance is detected, the selector selects anotherone of the tuners TUi, and the conformance test is repeated. Theconformance signal CON may be outputted to indicate the status of thetest to, for example, the user via a microcontroller. The conformancesignal CON may be provided on a digital output bus.

Due to the controller CO and the directing circuit DIR in accordancewith the invention, it is possible to test a significant part of themain receiver MR. Further, if the controller comprises the tunercontroller TUC, the detector DET, and the frequency setting circuit FSCshown in FIG. 5, it is possible to automatically set the modulatorfrequencies of the modulators MODi such that they do not coincident withthe frequencies of the channels in which a broadcasting is present. Thismay improve the performance of the system which comprises the mainreceiver MR and the auxiliary receivers AR1 and AR2 considerably byavoiding interferences between the present broadcasts and the modulatorfrequencies.

FIG. 7 shows a block diagram of another embodiment of a main receiver ofthe system in accordance with the invention.

The main receiver MR comprises a high-frequency switching matrix RFSMwhich is able to connect any of its inputs INi or the signals HFOSi toany of its outputs OUTi or to any of the tuner inputs TUIi. It is alsopossible to connect the same input INi or output OUTi to several outputsOUTi or inputs INi, respectively.

The switching matrix RFSM has inputs INi for receiving thehigh-frequency input signal HFIS from the high-frequency splitter HFS1,and inputs for receiving the high-frequency output signals HFOSi of themodulators MODi

The switching matrix RFSM has outputs OUTi to supply the high-frequencyinput signals HFSI to the tuner inputs TUIi, the high-frequency outputsignals HFOSi to the high-frequency combiner HFC1.

The test signals TSi from the controller CO are supplied to therespective modulators MODi. The tuner output signals TOSi are suppliedto the demodulator DEM and to the controller CO. Instead of the tuneroutput signals TOSi, it is also possible to supply the demodulatoroutput signals DESi to the controller CO.

The input of the expander HFS1 is connected to the input terminal viathe combiner HFC4 which adds the upstream signal US from the upstreamsignaling circuit DOC. This enables communication to the provider, whichis important when applications like video-on-demand or internet arerequired.

The combiner HFC1 generates the combined high-frequency signals CHFOSi.The combined high-frequency signal CHFOS1 is supplied to the outputterminal OT1, and the combined high-frequency signal CHFOS2 is suppliedto the output terminal OT2.

The combined high-frequency signal CHFOS3 is supplied to an input of thehigh-frequency switching matrix RFSM. This enables to check a doublepath through the switching matrix. For example, it is possible to createa path from the modulator MODn, via a matrix input INi, a matrix outputOUTj to matrix input INk and matrix output OUT1 to the tuner TU1 (theindices are an example only). Now, two paths trough the matrix RFSM areinvolved and the information is obtained about the performance of thematrix RFSM.

This switching matrix RFSM has the advantage that it can be incorporatedin an integrated circuit much more efficiently and cost-effective, thiscontrary to the high-frequency combiners which are because of thismostly discrete components. A further advantage is that the loop-throughfrom the signal on the input terminal INT to the output terminals OT1and OT2 can be performed by the switching matrix RFSM. Now, it can bechecked also whether this loop-through function is operating correctly.

It should be noted that the above-mentioned embodiments illustraterather than limit the invention, and that those skilled in the art willbe able to design many alternative embodiments without departing fromthe scope of the appended claims. For example, instead of thehigh-frequency couplers

In the claims, any reference signs placed between parenthesis shall notbe construed as limiting the claim. The word “comprising” does notexclude the presence of other elements or steps than those listed in aclaim. The invention can be implemented by means of hardware comprisingseveral distinct elements, and by means of a suitably programmedcomputer. In the device claim enumerating several means, several ofthese means can be embodied by one and the same item of hardware.

1. An in-home receiver system with a main receiver and at least onefurther receiver, the main receiver comprising: at least one tuner witha tuner input for receiving a high-frequency input signal and a tuneroutput for supplying a tuner output signal, at least one modulator forreceiving a modulator input signal to supply a high-frequency outputsignal to the at least one further receiver, a test signal generator forsupplying a test signal to the at least one modulator, a directingcircuit for directing the high-frequency output signal to the tunerinput, and a test evaluator for evaluating whether the tuner outputsignal is in conformance with the test signal.
 2. An in-home receiversystem as claimed in claim 1, wherein the main receiver furthercomprises a switch control circuit for supplying a switching signal tothe directing circuit, and the directing circuit further comprises aswitch for supplying either the high-frequency input signal or thehigh-frequency output signal to the tuner input under control of theswitching signal.
 3. An in-home receiver system as claimed in claim 1,wherein the main receiver further comprises a switch control circuit forsupplying a switching signal to the directing circuit, and the directingcircuit further comprises a series arrangement of a high-frequencycoupler and a switch being controlled by the switching signal, theseries arrangement being arranged between the tuner input and an outputof the modulator for supplying either the high-frequency input signalwhen the switch is open or the high-frequency input signal together withthe high-frequency output signal to the tuner input when the switch isclosed.
 4. An in-home receiver system as claimed in claim 1, wherein thetest signal comprises a sine wave at a predetermined frequency, or a bitsequence.
 5. An in-home receiver system as claimed in claim 1, whereinthe test signal generator comprises a modulator frequency controller forcontrolling the at least one modulator to vary a frequency of thehigh-frequency output signal through a desired frequency band.
 6. Anin-home receiver system as claimed in claim 1, wherein the in-homesystem comprises a plurality of tuners, each with a tuner input forreceiving a high-frequency input signal and a tuner output for supplyinga tuner output signal, a selector for selecting one of the plurality oftuner output signals, a test evaluator for producing a conformancesignal if the output signal of the selected one of the tuner outputsignals is in conformance with the test signal, the selector furtherbeing arranged for selecting an other one of the plurality of tuneroutput signals if the conformance signal indicates that the outputsignal of the selected one of the tuners is in not in conformance withthe test signal.
 7. An in-home receiver system as claimed in claim 1,wherein the controller comprises a tuner controller for controlling theat least one tuner to scan through at least part of the high-frequencyband to be received, a detector for detecting at which frequencies inthe at least part of the high-frequency band a broadcast signal ispresent, and a frequency setting circuit for setting a modulationfrequency of the at least one modulator to interleave with thefrequencies in the at least part of the high-frequency band at which abroadcast signal is present.
 8. An in-home receiver system as claimed inclaim 1, wherein the controller further comprises a timing circuit forsupplying the test signal at regular time intervals.
 9. An in-homereceiver system as claimed in claim 1, wherein the main receivercomprises: a plurality of tuners with respective tuner inputs forreceiving the high-frequency input signal and respective tuner outputsfor supplying tuner output signals, an input terminal for connecting aninput coaxial cable to supply the high-frequency input signal comprisinga broadcast signal, a first high-frequency splitter for supplying thehigh-frequency input signal to the tuner inputs, a demodulator circuitfor receiving the tuner output signals to supply respective demodulatedor decoded video and/or audio signals, a plurality of modulators coupledto the demodulator circuit for receiving respective modulator inputsignals to supply high-frequency output signals, a first high-frequencycombiner for combining the high-frequency output signals into aplurality of combined high-frequency output signals, a first outputterminal for supplying a first one of the plurality of combinedhigh-frequency output signals to a first one of a plurality of auxiliaryreceivers via a first output coaxial cable, a second output terminal forsupplying a second one of the plurality of combined high-frequencyoutput signals to a second one of the plurality of auxiliary receiversvia a second output coaxial cable, the test signal generator forsupplying the test signal to at least one of the plurality ofmodulators, the directing circuit for directing a third one of theplurality of combined high-frequency output signals to an input of thefirst high-frequency combiner, and a test evaluator for evaluatingwhether tuner output signals are in conformance with the test signal.10. An in-home receiver system as claimed in claim 9, wherein the mainreceiver further comprises: a first high-frequency coupler coupled tothe input coaxial cable, a second high-frequency splitter coupled to thefirst high-frequency coupler for supplying the high-frequency inputsignal to a second high-frequency coupler and a third high-frequencycoupler, the second high-frequency coupler being coupled to the firstoutput coaxial cable and a third high-frequency coupler being coupled tothe second output coaxial cable.
 11. An in-home receiver system asclaimed in claim 9, wherein the main receiver further comprises ahigh-frequency switching matrix having inputs for receiving thehigh-frequency input signal from the first high-frequency splitter, thehigh-frequency output signals of the modulators, the test signals of thetest signal generator, and the tuner output signals, and having outputsto supply the high-frequency input signal to the tuner inputs, thehigh-frequency output signals to the first high-frequency combiner, andthe test signals and/or the tuner output signals as the modulator inputsignal to the modulators.
 12. An in-home receiver system as claimed inclaim 11, wherein the high-frequency switching matrix further has aninput for receiving the high-frequency output signal.
 13. An in-homereceiver system as claimed in claim 1, wherein the main receiver furthercomprises a circuit for adding an upstream signaling stream onto thehigh-frequency input signal.
 14. A main receiver for use in the in-homereceiver system as claimed in claim 1, and comprising: at least onetuner with a tuner input for receiving the high-frequency input signaland a tuner output for supplying a tuner output signal, at least onemodulator for receiving a modulator input signal to supply ahigh-frequency output signal to the at least one further receiver, atest signal generator for supplying a test signal to the at least onemodulator, a directing circuit for directing the high-frequency outputsignal to the tuner input, and a test evaluator for evaluating whetherthe tuner output signal is in conformance with the test signal.
 15. Inan in-home system comprising: at least one further receiver, and a mainreceiver comprising at least one tuner with a tuner input for receivinga high-frequency input signal and a tuner output for supplying a tuneroutput signal, and at least one modulator for receiving a modulatorinput signal to supply a high-frequency output signal to the at leastone further video receiver, a method of testing the main receivercomprising: supplying a test signal to the at least one modulator,directing the high-frequency output signal to the tuner input, andevaluating whether the tuner output signal is in conformance with thetest signal.